Recently, multimedia electronic devices that provide information to users have been actively developed and launched.
As a representative example of these multimedia electronic devices, there is a mobile device such as a smartphone.
The mobile device has both mobility and portability and includes various functions such as phone call, listening to music, video watching, message transmission and reception, scheduling, Internet surfing, and the like.
On the other hand, research has been conducted to apply these multimedia electronic devices to vehicles.
In order to receive input commands for performing various functions of the multimedia electronic device, various buttons are installed in the exterior of the multimedia electronic device. A user can operate various buttons to perform the corresponding functions.
However, it is difficult for the user to know what functions are performed by the various buttons. Even though the user knows the corresponding functions of the buttons, it is very inconvenient for the user to perform operations by pressing the corresponding buttons one by one.
Furthermore, in the case of a small-sized multimedia electronic device, a gap between the respective buttons is narrow due to a limitation of an occupied area thereof, there is a problem that malfunction occurs due to a user's wrong button selection.